The present invention relates to an electronic digital scale, wherein a length is measured through the movement of an extensible member and then is indicated on a digital display after being processed by a detection circuit.
In the art of measurements, a single vehicle, for example, a sprocket was provided to detect the length of extension of an extensible tape member, which was rotated in union with the movement of the tape member. See, for example, U.S. Pat. No. 3,526,890, entitled "LINEAR TAPE TRANSDUCER" assigned to Anilam Electronics Corporation. However, such a detection system required at least two sprockets to measure the bidirectional movement of the extensible tape member. This made an electronic digital scale unavoidably complex.